This invention relates to a probe for the measurement of the vapor velocity, density, temperature, and flow direction of vapors, such as metal vapors, in a vapor plume from a vaporization source.
It is desirable to know the characteristics of the vapor in a vapor plume, including the density, velocity, temperature, and direction of flow of the vapor emanating from a vapor source so that use of the vapor source, for example, for coating of a substrate, may be optimized. By knowing the flux (density and velocity) of the vapor in the vapor plume, one may be able to determine, for example, how to move either the vapor source or the object to be coated, in a manner which will result in achieving a uniform coating on the object to be coated.
In the past, several different methods have been employed to obtain such information, with each method having significant drawbacks. These methods include multiple discrete shots through the total vapor plume and multiple discrete local measurements at various angles, as well as time averaged methods such as measuring the coating shadow past a hard edge after the run is over. In general, however, such methods are either significantly more complicated in both hardware and analysis or are less quantitative and incomplete as compared to a vapor probe.